Museums are quiet, clean spaces designed to encourage the contemplation of history and art. They are also, it turns out, the perfect setting for a book about a talking horse.

Horse Museum is the second “lost book” from Theodor Geisel (Dr. Seuss), found amid a number of manuscripts and illustrations by the late author’s wife Audrey Geisel in 2013. The first of these lost books, What Pet Should I Get?, hit shelves in 2015 and went on to become the fastest-selling picture book in Random House Children’s Books history. Horse Museum launched in September, and explores the different ways artists have represented horses throughout history.

“The premise of the book is that, across the ages, man has created art based on horses—from cave drawings all the way to modern artists like Picasso and Pollock,” says Susan Brandt, president of Dr. Seuss Enterprises.

Despite their shared subject matter, though, all of the works of art featured in the book look different. The book’s horse tour guide teaches kids about artistic concepts like realism and impressionism, and invites them to think about what an artist might have been trying to say through their work.

And while What Pet Should I Get? was discovered in the pen and ink stage (with completed text and art finished except for the color), Horse Museum was in a much more unfinished state, and therefore took longer to publish.

“We needed to find the right illustrator for Horse Museum,” Brandt says. “And frankly, we’re depicting historical works of art, so there were approvals and permissions we had to get.”

Andrew Joyner (The Hair Book, The Pink Hat) was chosen to illustrate the book, and inspired by its message about artistic expression, interpreted Dr. Seuss’s visual style rather than recreating it. Joyner incorporated classic Seuss characters into the background of several pages as Easter eggs for longtime fans. The mix of classic characters and artistic expressionism inspired a number of decisions around the initial consumer products program, which includes arts and crafts supplies (Leap Year Publishing), school supplies (GEDDES), plush (Aurora) and apparel and accessories (Merch by Amazon). The first products will hit shelves in Q4, with additional items rolling out into 2020. Packaging will focus primarily on classic Seuss characters like The Cat in the Hat.

“It’s tricky when you have this lost book,” Brandt says. “Part of the fun is that we’re not going to show you everything—we’re going to build the anticipation so that people rush to see what’s inside. It doesn’t make sense to take that art and provide it to individual licensees who are working 12 to 18 months out, and presenting to retail. It’s kind of like, that cat’s out of the bag.”

But this secretive approach also presents challenges. With What Pet Should I Get?, there was a missed opportunity when—in an effort to keep things under wraps—the company ultimately chose not to pursue consumer products in a significant way in the lead-up to the book’s launch, she says. By creating a guide that focused on classic characters, Dr. Seuss Enterprises could provide assets to partners that would see spoiler-free products hit shelves in a timely manner for Horse Museum.

Items from Merch by Amazon, though, will feature art from the new book because the on-demand platform has significantly shorter lead times than traditional licensing partners.

“Because it’s such a short window, we can have some images of the new horse character,” Brandt says. “We can get that up very quickly. I think, overall, we came up with a beautiful solution for consumer products that feels really natural because of the way the book is written and illustrated.”